docs: def create_optparser(progname=None):
      """
      an OptionParser instance filled with options and groups
      appropriate for use with the distdiff command
      """
      from . import report
  
      parser = ArgumentParser(prog=progname)
      parser.add_argument("dist", nargs=2,
                          help="distributions to compare")
  
      add_general_optgroup(parser)
      add_distdiff_optgroup(parser)
      add_jardiff_optgroup(parser)
      add_classdiff_optgroup(parser)
  
      report.add_general_report_optgroup(parser)
      report.add_json_report_optgroup(parser)
      report.add_html_report_optgroup(parser)
  
      return parser